Exposure to exogenous agents that damage the cell is an unavoidable and potentially deleterious component of life, though various cellular responses exist to counter these exposures. It is understood that these countermeasures are vital for both cellular and organism fitness and is key to understanding disease predisposition, individual sensitivity to environmental exposures and developing medicine. However, we still lack significant knowledge in what responses are involved in environmentally induced damage and, even for those responses we have identified, many mechanistic details are lacking. Our hypothesis is that (a) the genes and pathways necessary to survive damage can be both damage-specific and -nonspecific, (b) despite differences for individual gene requirements in surviving different damages, they may share the same basic pathways for survival and (c) we can determine novel functions for identified proteins based on interactions with proteins already known to function in damage survival. This premise is supported by our preliminary data. Our goal is to identify damage survival mechanisms in mammalian cells. Using the model organism Drosophila and RNA interference we identified genes and pathways necessary for cells to survive different DNA damaging agents, such as proteasome activity. Once these genes are determined in Drosophila cells, we can test whether the same genes contribute to survival in mammalian cells. Indeed, we already successfully used this strategy to identify novel alkylation survival genes and pathways in mouse and human cells and demonstrated that pathways critical in Drosophila are also involved in mammalian damage response. Here we propose to leverage this strategy by first completing the validations for two additional survival screens of agents that cause different forms of damage, bleomycin and ultraviolet light. In Aim 1, we prioritize the screen results, complete screen validations, and identify novel survival genes and pathways not previously known to be involved in damage survival, demonstrating the functional conservation of these pathways in mouse embryonic fibroblasts. The focus of the latter part of this aim will be on novel proteins and differences between damaging agents within established survival pathways. In Aim 2, we take a reverse strategy, identifying survival proteins that alter damage induced proteasome activity, investigate the mechanism of their interaction with proteasome and differences between damage types. Available information on established pathways and protein: protein interaction network maps will facilitate this work. We are uniquely positioned to carry out the proposed work with the necessary infrastructure, collaborators and technical expertise, as demonstrated by our publications and our preliminary data that supports our hypothesis. In summary, this research will provide insights into the complicated biology of damage response and survival, identifying novel genes that may be important for gene/environmental interactions, disease predisposition and chemo-therapeutic intervention. Future directions will be to apply the knowledge gained to pertinent disease models. PUBLIC HEALTH RELEVANCE: Environmental exposures are a normal and unavoidable consequence of life, however, the resultant cellular damages must be counteracted in order maintain cellular and organism fitness. Deficiency in a countermeasure is one basis for disease predisposition or sensitivity to particular environmental agents. Here we propose to identify novel components to these countermeasures necessary for damage survival, improve our understanding of how these and already established countermeasures interact and set the groundwork for future work to harness this knowledge to improve disease prediction and treatment.